The field of the invention is valves, and the invention relates more particularly to remote controlled valves which are operated by injecting or withdrawing small volumes of air into a diaphragm-containing control valve.
Applicants' assignee is filing a patent application showing a hand operated push button assembly and a foot operated push button assembly connectable to a remotely controlled valve, which application was filed on the same day as the present application and is identified by Ser. No. 823,393. This application describes in detail the construction and operation of both the hand operated push button and the foot operated push button in conjunction with the remotely controlled valve. The specification of that application is incorporated by reference to provide further non-essential information on the details of construction of the push button. Although the push button and valve assembly described therein operates satisfactorily either with the hand button, alone, or with the foot button, alone, for some applications, it is beneficial to provide operation by either the hand button for a timed volume of water or by the foot button for a continued flow of water as long as the foot button is depressed. Unfortunately, the connection of both the hand and foot button to the same valve provided an inoperative device for several reasons. The hand operated button operates by expelling a small volume of air as the push button is depressed, and the opening of the valve is caused only when the push button is released and a volume of air is extracted from below the diaphragm of the remotely controlled valve. In order for the push button to operate, there must be some means for the air to escape when the hand operated push button is depressed. When the remotely controlled valve is operated only by the hand operated push button, the upper chamber of the controlled valve is simply left open to the atmosphere. This, however, would make the foot operated button inoperative since pressure must be maintained in the upper chamber of the controlled valve to hold it open. Furthermore, the timing of the hand operated push button results from the metered entry of air through a needle valve into the lower chamber which eventually equalizes the pressure on both sides of the diaphragm of the remotely controlled valve causing it to close. However, when the foot button is held in a downward position, air flows into the upper chamber of the remote pneumatic servomotor and a volume of air from below the diaphragm in the remote pneumatic servomotor flowed outwardly through the needle valve reducing the pressure below the diaphragm. When the foot button is released, the pressure below the diaphragm has become insufficient to cause the diaphragm to return to its neutral position opening the valve and, therefore, the valve stays open for a timed period after the foot button is released. This resulted in unsatisfactory operation of the foot operated button.
There is, thus, a need for an assembly which may be operated by either a hand operated push button causing a timed opening of a water valve and a foot operated push button which causes the water valve to remain open as long as the foot button is depressed.